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Patented Feb. 3, 1931 SHINJIRO HORII, F 'TOKYQ, JAPAN:

No Drawing. Application filed. June 26,

I My invention relates to improvements in stencil sheets of the type commonly used for autographic and typewritingduplication, consisting of a sheet of fibrous material having a coating which is impermeable to ink and can be stencilized by the pressure of a writing stylus or by the impact 'of the type of a writing machine. It has previously been proposed to produce a stencil sheet of this kind such as a base of fibrous material, having Japanese Yoshino paper, coated with a composition including a cellulose ester, such as cellulose acetate or nitrate, dissolved in a-volatile solvent,-such as alcohol-ether mixture or amyl-acetate, and a tempering agent such as castor oil, soya bean oil, hydro-carbon oil or oleic acid.

It'has also been proposed to roduce such a stencil sheet having a fibrous ase which is coated with a composition including esters of polysaccharides and a tempering agent such as naphthenic acid glycerides, chlorinated naphthalene or fatty acid of tsubaki oil.

The stencil sheet of the present invention comprises a fibrous base coated with a coating material consisting of a solution of esters of polysaccharides in a volatile solvent in admixture with dolphin oil.

Dolphin oil is obtained from the blubber of the various species of dol hin belonging to the Delphim'dae, such as, De phimls Zongros- Wis, Gray (mairuka), Delphz'nus glabz'ceps, I

Lam. (black fish or bottlenose dolphin), Lageno'rhynclms acutus, Gray (kamairuka),

Delphnus phocwna, L. (brown porpoise),

Phocoemt commwmz's Less (nezumi iruka), Globz'ooephalus sz'eboldz'z', Gray (pilot-whale) etc. The oils from the jaw and from the body differ considerably in composition. These oils contain notable amounts of sperm-aceti, forming intermediate members between fatty oils and liquid waxes. Moreover, these oils occupy an exceptional position on account of their containing considerable proportions of glycerides of volatile acids.

In this connection it may he noted that the employment of a magin'e wax, such as spermaceti, sperm oil, bottle-nose oil, or other 1928. Serial No. 287,051.

analogous substances derived from the allied species of salt-water fish in admixture with fatty oils, fats or fatty acids has been proposed in the production of stencil sheets. It has also been suggested to produce a stencil sheet of afibrous basehaving a type impressible coating thereon, consisting of a base of law dissolved in alcohol, and having added thereto dissolved nitrated cotton, camphor, castor oil and sperm oil. Spermaceti orsperm 4'. oil is a true wax, in solid or fluid state, consisting chiefly of compound esters of fatty acids and monovalent alcohols. It is found, however, that sperm oil in association with esters of polysaccharides as a tempering agent, is entirely unsuitable, having the drawback of being a coating not suficiently tough and being easily crumbled or cracked on the surface when handled. According to the present invention, the ink-proof coating consists of a homogeneous mixtureof esters of polysaccharides and dolphin oil. Dol hin oil forms an intermediate link between w ale oil (consisting nearly wholly of glycerides) and sperm oil (a true wax). Dolphin oil has a suitable density and limpidity even at low temperatures, and, when it is used in the production of a stencil sheet for coating the same, in admixture with the esters of polysaccharides, the coating is perfect and uniform, and a stencil sheet is produced which is easily stencilized making clear impressions.

In the practice-of the invention, a sheet of .fibrous base, such as Japanese Yoshino paper,

is coated or impregnatedwith a coating material prepared by esters of polysaccharides, such as starch acetate, mannan acetate, cellulose acetate and cellulosenitrate, being dissolved in a suitable solvent, such as acetone, alcohol, ethyl acetate, amyl acetate, benzine and benzol, or amixtureof them, to which dolphin oilhas been added.

To a given quantity of this material a suit- I able quantity of whale oil, neats foot oil, lard oil or naphthenic acid glycerides may be added in admixture with the dolphin oil. And also, if desired, a tempering agent such as hydrocarbon oil's, fatty oils, naphthenic acid glycerides, oils, fats, fatty acids, waxes, triacetin, butyl tartrate, ethyl or butyl phthalate, triphenyl or tricresyl phosphate, or a mixture of them may be added to the above described coating material. The coating ma terial may be added into the paper stufi" ina mixing hollander during-the paper making Q operation. i

The proportions of the ingredients of the composition may vary according to several circumstances. The following is an example:

- Parts by 3 weight Cellulose nitra Amyl acetate Ethyl acetate 3O Ethyl alcohol 20 1 Benzoll 30 Dolphin nil .Naphthenic acid glycerides 5 The term esters of polysaccharides is intended to include not only one of definite esters of polysaccharides, but also a mixture ofthem. x

What I claim is: l." A stencil sheet adapted for stencilizing by pressure, consisting of a base of fibrous material having a coating including esters of polysaccharides and dol hin oil.

2. A stencil sheet adapte for stencilizing by pressure, consisting of a base of fibrous material having a coating including esters of polysaccharides, dolphin oil, and tempering agents. 1 3. A stencil sheet adapted for stencilizing by pressure, consisting of a base of fibrous material having a coating including esters of polysaccharides, dolphin oil and other oils. In testimony whereof I afiix my si ature.

SHINJIRO H RH. 

